Note: Descriptions are shown in the official language in which they were submitted.
~1191~
One of the most well-known and widely used class of antibacterial
agents are the so-called ~-lactam antibiotics. These compounds are
characterized in that they have a nucleus consisting of a 2-azetidinone
(~-lactam) ring fused to either a thiazolidine or a dihydro-1,3-thiazine
ring. When the nucleus contains a thiazolidine ring, the compounds are
usually referred to generically as penicillins, whereas when the nucleus
contains a dihydrothiazine ring, the compounds are referred to as cephalos-
porins. Typical examples of penicillins which are commonly used in clinical
practice are benzylpenicillin ~penicillin G), phenoxymethylpenicillin
(penicillin V), ampicillin and carbenicillin; typical examples of common
cephalosporins are cephalothin, cephalexin and cefazolin.
However, despite the wide use and wide acceptance of theJB-lactam
antibiotics as valuable chemotherapeutic agents, they suffer from the major
drawback that certain members are not active against certain microorganisms.
It is thought that in many instances this resistance of a particular micro-
',,~ ~
'` ~ 111~16g
organism to a given B-lactam antibiotic results because the microorganism
produces a ~-lactamase. The latter substances are enzymes which cleave the
~-lactam ring of penicillins and cephalosporins to give products whiCh are
devoid o~ antibacterial activity. However~ Certain substances have the ability¦
to inhibit ~-lactamases, and when a ~-lactamase inhibitor is used in combina-
tion with a penicillin or cephalosporin it can increase or enhance the anti-
bacterial effectiveness of the penicillin or cephalosporin against certain
microorganisms. It is considered that there is an enhancement of antibacterial
effectiveness when the antibacterial activity of a combination of a B-lacta-
mase inhibiting 8ubstance and a ~-lactam antibiotic is significantly greater
than the sum of the antibacterial activities of the individual components.
Thus, according to the invention, there are provided certain new
chemical compounds Which are new members of the class of antibiotics known
l as the penicilliDs, and which are useful as antibacterial!agents. Nore
specifically, these new penicillin compo~mds are penicillanic acid l,l-dioxide,
~and esters thereof readily hydrolyzable in vivo.
¦ Additionally~ penicillanic acid l,l-dioxide and its esters readily
¦hydrolyzable in vivo are potent inhibitors of microbial ~-lactamases.
¦ Accordingly~ there is also provided a method for enhancing the effectiveness
lof ~-lactam antibiotics, using penicillanic acid l,l-dioxide and certain
,readily hydrolyzable esters thereof.
Still further~ there are provided derivatives of penicillanic acid
dioxide having a carboxy protecting group~ said compounds being useful
¦a8 chemical intermediate8 for penicillanic acid l,l-dioxide.
'I - . ,
111916~
Yet further, there are provided penicillanic acid l-oxides, and
¦certain esters thereof, as chemical intermediates to penicillanic acid 1,1-
dioxide.
l,l-Dioxides of benzylpenicillin, phenoxymethylpenicillin and certain
esters thereof have been disclosed in ~nited States Patents 3,197,466 and
3,536,698, and in an article by Guddal et al., in Tetrahedron Letters, No. 9,
381 ~1962). Harrison et al., in the Journal of the Chemical SocietY (Londonj,
Perkin I, 1772 (1976), have disclosed a variety of penicillin l,l-dioxides and
l-oxides, including methyl phthalimidopenicillanate l,l-dioxide, methyl 6,6-
dibromopenicillanate l,l-dioxide, methyl penicillanate l~-oxide, methyl
penicillanate lB-oxide, 6,6-dibromopenicillanic acid l-oxide and 6,6-dibromo-
penicillanic acid lB-oxide.
Su~marY of the Invention
According to the invention there are provided novel compounds of the
lS formula
. . . '.'
-
~ 1119164 ~ I
¦ and the pharmaceutically-acceptable base salts thereof, wherein Rl is selected
¦ from the group consisting of hydrogen, ester-forming residues readily
¦ hydrolyzable in vivo, and conventional penicillin carboxy protecting groups.
¦ The term "ester-forming residues readily hydrolyzable in v '~is here
¦ intended to refer to non-toxic ester residues which are rapidly cleaved in
¦ mammalian blood or tissue, to release the corresponding free acid (i.e. the
compound of formula I, wherein R is hydrogen). Typical examples of such
¦ readily hydrolyzable ester-forming residues which can be used for Rl are
I alkanoyloxymethyl having from 3 to 8 carbon atoms, l-(alkanoyloxy)ethyl having
10 ¦ from 4 to 9 carbon atoms, l-methyl-l-(alkanoyloxy)ethyl having from 5 to 10
carbon a.oms, alkoxycarbonyloxymethyl having from 3 to 6 carbon atoms,
¦ l-(alkoxycarbonyloxy)ethyl having from 4 to 7 carbon atoms, l-methyl-l-(alkoxy-
¦ carbonyloxy)ethyl having from 5 to 8 carbon atoms, 3-phthalidyl, 4-crotono-
I lactonyi and y-butyrolacton-4-yl.
¦ The compounds of the formula I, wherein R is hydrogen or an ester-
¦ forming residue readily hydrolyzable in vivo, are useful as antibacterial agent 3
and for enhancing the antibacterial activity of ~-lactam antibiotics. Said
¦ compounds of the formula I, wherein Rl is a penicillin carboxy protecting
I group, are useful as chemical intermediates to the compound of the formula I,
¦ wherein R is hydrogen or an ester-forming residue readily hydrolyzable in vivo
¦ Typical carboxy protecting groups are benzyl and substituted benzyl, e.g.
¦ 4-nitrobenzyl.
ll ~119~.6
-. I
¦ A1BO accorBin~ to the invention thare are provided novel co~pounds .
of the fO--UL COOR1
. and
oC~ 1 ~~~ (llr~
1. , I
_ ¦1 and the 6alts thereof, wherein Rl i8 a6 defined previsua1y. Said comFounds ~'
,il of the formulas II and III are intermediates to said compounds of the formula
~1 I. .
Il . . '
I Dctailed Description of the Invention
~ This invention relates to the novel compounds of formulas I, II and
¦~ III, and throu~hout this specification they are.referred to as derivatives of .
~¦ penicillanic acid, which is representad ~y the 6tructural formula
F~ CR3 _--(IV~
COOH
9~
.,
.1
¦ In formula IV, broken line attachment of a su~sti~uent to tbe bicyclic nucleus ¦
indicates that the substituent i9 below the plane ~f the bicyclic nucleus.
I Such a substituent i8 6aid to be in the ~-confi~uration. Conversely, solid
¦ line attachment of a 6ubstituent to the bicyclic nucleus indicates ~ha~ the
5. ¦¦ substituent is ateached above the plane of ~he nucleu6. This laeter config-
¦l uration is referred to as the ~-configuration. -
I Also in this 6pecification reference is made to certain derivatives
of cephalosporanic acid, which ~las the ~ormula
' S, I
COOH
o l! In formula V, the hydrogen at C-6 is below the plane of the bicyclic nucleus.
¦ ~he derived terms desacetoxycephalosporanic acid and 3-desacetoxymethylcephalo-¦
¦ sporanic acid are u6ed to refer to the 6tructures VI and YII, respectively.
' H
FS ~ . ',~ S~
¦l O ~ CH3 O ~ ~
COOH COOH
¦I VI VII
Il 4-Crotonolactonyl and y-butyrolacton-4-yl refer to
15¦ 6tructure6 VIII~,and IX, respectively. The wavy line6 are ineended to denote
each of the two epimers and mixtures thereof.
VIII
~ 6
1, . 1.
1119164
When Rl is an ester-forming residue readily hydrolyzable in vivo
in a compGund of formula I, it is a grouping which is notionally derived from
an alcohol of the formula Rl-OH, such that the moiety COOR in such a compound
of formula I represents an ester grouping. Moreover, R is of such a nature
that the grouping COORl is readily cleaved in in vivo to liberate a free car-
boxy group (COO~). That is to say, R is a group of the type that when a
compound of formula I, wherein R is an ester-forming residue readily hydrolyze d
in VivoJ is exposed to mammalian blood or tissue, the compound of formula I,
wherein R is hydrogen, is readily produced. The groups Rl are well-known
in the penicillin art. In most instances they improve the absorption
characteristics of the penicillin compound. Additionally, Rl should be of
such a nature that it imparts pharmaceutically-acceptable properties to a
compound of formula I, and it liberates pharmaceutically-acceptable fragments
when cleaved in vivo. !
As indicated above, the groups R are well-known and are readily
identified by those skilled in the penicillin art. See, for example,
West German Offenlegungsschrift No. 2,517,316. Typical groups for R are
3-phthalidyl, 4-crotonolactonyl, y-butyrolacton-4-yl and groups of the formula
- I-o-C-R5 and -C-O-C-O-R
l4 R4
X XI
.~ .
~ - 6a
__ . ~
111~16~
wherein R3 and R4 are each selected from the group consisting of hydrogen and
alkyl ha~ing from 1 to 2 carbon atoms, and R5 is alkyl having from 1 to 6 car-
~bon atoms. However, preferred groups for Rl are alkanoyloxymethyl having from
3 to 8 carbon atoms, l-~alkanoyloxy)ethyl having from 4 to 9 carbon atoms, 1-
¦ methyl-l-(alkanoyloxy)ethyl having from 5 to 10 carbon atoms, alkoxycarbonyloxy-
¦ methyl having from 3 to 6 carbon atoms, l-(alkoxycarbonyloxy)ethyl having from
14 to 7 carbon atoms, l-methyl-l-alkoxycarbonyloxy)ethyl having from 5 to 8
~ '.; '
~ ' .,
. l
I -6~-
: :. , . :
~119164
The compounds of formula I, wherein R is as defined previously can
be prepared by oxidation of either of the compounds of formula II or III,
wherein R is as defined previously. A wide variety of oxidants known in the
art for the oxidation of sulfoxides to sulfones can be used for this process.
However, particularly convenient reagents are metal permanganates, such the
alkali metal permanganates and the alkaline ear*h metal permanganates, and
organic peroxy acids, such as organic peroxycarboxylic acids. Convenient -
individual reagents are sodium permanganate, potassium permanganate, 3-
chloroperbenzoic acid and peracetic acid.
When a compound of the Formula II or III, wherein Rl is as defined
previously, is oxidized to the corresponding compound of t~e formula I using
a metal permanganate, the reaction is usually carried out by treating the
compound of the formula II or III with from about 0.5 to about 5 molar
equivalents of the permanganate, and preferably about`l molar equivalent of
the permanganate, in an appropriate solvent system, An appropriate soIvent
system is one that does not adversely interact with either the starting
materials or the product, and water is commonly used. If desired, a co-solvent
which is miscible with water but will not interact with the permanganate, such
as tetrahydrofuran, can be added. The reaction is normally carried out at a
temperature in the range from about -20 to about 50 C., and preferably at
about 0 C. At about 0 C. the reaction is normally substantially complete
within a short period, e.g. within one hour. Although the reaction can be
carried out under neutral, basic or acid conditions, it is preferable to -
operate under substantially neutral conditions in order to avoid decomposition
of the B-lactam ring system of the compound of the formula I. Indeed, it is
often advantageous to buffer the pH of the reaction medium in the vicinity
of neutrality. The product is recovered by conventional techniques. Any
excess permanganate is usually decomposed using sodium bisulfite, and then
if the product is out of solution, it is recovered by filtration. It is
~==z:_.
1119~69~
separated from manganese dioxide by extracting lt into an organic solvent and
removing the solvent by evaporation. Alternatively, if the product is not
out of solution at the end of the reaction, it is isolated by the usual
procedure of solvent extraction.
When a compound of the formula II or III, wherein R is as previously
defined, is oxidized to the corresponding compound of the formula I, using
an organic peroxy acid, e.g., a peroxycarboxylic acid, the reaction is usually
carried out by treating the compound of the formula II or III with from about
1 to about 4 molar equivalents, and preferably about 1.2 equivalents of the
oxidant in a reaction-inert organic solvent. Typical solvents are chlorinated
hydrocarbons,such as dichloromethane, chloroform and 1,2-dichloroethane;
and ethers, such as diethyl ether, tetrahydrofuran and 1,2-dimethoxyethane.
The reaction is normally carried out at a temperature of from about -20
to about 50 C., and preferably at about 25C. At about 25~C. reaction times
¦of about 2 to about 16 hours are commonly used. The product is normally
¦isolated by removal of the solvent by evaporation in vacuo. The product
¦can be purified by conventional methods, well-~nown in the art.
When oxidizing a compound of the formula II or III to a compound
of the formula I using an organic peroxy acid, it is sometimes advantageous
¦to add a catalyst such as a manganese salt, e.g. msnganic acetylacetonate.
The compound of the formula I, wherein Rl is hydrogen, can also be
obtained by~removal of the protecting group Rl from a compound of the
formula I, wherein R is a penicillin carboxy protecting group. In this
context, Rl can be any carboxy protecting group conventionally used in the
penlcillin art to protect carboxy groups at the 3-position. The identity
of the carboxy protecting group is not critical. The only requirements
for the carboxy protecting group Rl are that: (l) it must be stable during
-
t
'11~91Ç;4
oxidation of the compound of formula II or III; and (il) it must be removable
from the compound of formula I, using conditions under which the ~-lactam re-
mains substantially intact. Typical examples which can be used are the tetra-
hydropyranyl group, the benzyl group, substituted benzyl groups (e.g. 4-nitro-
benzyl), the benzylhydryl group, the 2,2,2-trichloroethyl group, the t-butyl
group and the phenacyl group. See further: United States Patents 3,632,850
and 3,197,466; British Patent No. 1,041,985, Woodward et al., Journal of the
American Chemical Society, 88, 852 (1966); Chauvette, Journal of Organic
ChemistrY, 3~, 1259 (1971); Sheehan et al., Journal of Organic ChemistrY, 29,
2006 (1964); and "Cephalosporin and Penicillins, Chemistry and Biology",
edited by H. E. Flynn, Academic Press, Inc., 1972. The penicillin carboxy
protecting group is removed in conventional manner, having due regard for
the lability of the ~-lactam ring system.
In like manner, compounds of the formula I, wherein R is as
previously defined, can be prepared by oxidation of a compaund of the formula
~ 3
O r~ 1 ~
COOR
wherein R i8 as previously defined. This is carried out in exactly the same
manner as described hereinbefore for oxidation of a compound of the formula II
or III, except that twice as much oxidant is usually used.
.___ _ .~
- ' '
~119164
Compounds of the formula I, wherein Rl is an ester-forming
residue readily hydrolyzable in vivo, can be prepared directly from the com-
pound of formula I, wherein X i6 hydrogen, by esterification. The specific
method chosen will depend naturally upon the precise structure of the ester-
forming residue, but an appropriate method will be readily selected by one
skilled in the art. In the case wherein R is selected from the group
consisting of 3-phthalidyl, 4-crotonolactonyl, y-butyrolacton-4-yl and groups
of the formula X and Xl, wherein R3, R4 and R5 are as defined previously,
they can be prepared by alkylation of the compound of formula I, wherein
is hydrogen, with a 3-phthalidyl halide, a 4-crotonolactonyl halide, a
y-butyrolacton-4-yl halide or a compound of the formula
R3 o R3 0
Q-l-o-CeR5 and Q-C-O-C-O-R
R4 R4
XII XIII
wherein Q is halo, and R3, R4 and R5 are as previously defined. The terms
"halide" and "halo" are intended to mean derivatives of chlorine, bromine and
lS iodine. The reaction is conveniently carried out by dissolving a salt of the
compound of formula I, wherein R is hydrogen, in a suitable, p~lar, organic
solvent, such 8S N,N-dimethylformamide, and then adding about one molar
equivalent of the halite. When the reaction has proceeded essentially to
¦¦ cot;~ tlon, the od=ct ls lsolated by ~tandard technlquell. It Is ofteD
. . ~
~ 9a -
I , ,
111916~
sufficient simply to dilute the reaction medium with an excess of water, and
then extract the product into a water-immiscible organic solvent and then
recover sa~e by solvent evaporation. Salts of the starting material which
are commonly used are alkali metal salts, such as sodium and potassium salt,
and tertiary amine saltæ, æuch as triethylamine, N-ethylpiperidine, N,N-
- dimethylaniline and N-methylmorpholine salts. The reaction is run at a
temperature in the range from about 0 to 100 C., and usually at about 25C.
The length of time needed to reach completion varies according to a variety
of factors, such as the concentration of the reactants and the reactivity of~
the reagentæ. Thus, when considering the halo compound, the iodide reacts
faster than the bromide, which in turn reacts faster than the chloride.
In fact, it is sometimes advantageous, when utilizing a chloro compound, to
add up to one molar equivalent of an alkali metal iodide. This has the effect
of spçeding up the reaction. With full regard for the for,egoing factors, .
reaction times of from about l to about 24 houræ are commonly used.
_ _. ~
., Il I
9~
'I , .
., ,,11 , . .,
!i 1Penicillanic acid l~-oxide, the compound of the formula II, wherein
R is hydro~en, can be prepared by tebromination of 6,6-dibromopenicillanic
l acit lu-oxide. The debromination can be carried o~t using a conventional
l hydrogenolysis technique. ~hus, a solution of 6,6-dibro penicillanic acid 1~-
oxide is stirred or shaken unter an atmosphere of hydrogen, or hydrogen mixed
. with an inert diluent such as nitrogen or ar~on, in the presence of a catalytic
amount of palladium-on-calcium carbonate catalyst. Convenient solvents for
I this debromination are lower-alkanols, such as methanol; ethers, such as tetra-
¦ hydrofuran and dioxan; low molecular weight esters, such as ethyl acetate andbutyl acetate; water; and mixtures of these solvents. However, it is usual to
choose conditions under which the dibromo compound is soiuble. The hydro-
¦¦ genolysis is usually carried out at room temperature and at a pressure from
I¦ about atmospheric pressure to about 50 p.s.l. The catalyst is usually present
I in an amount from about 10 percent by weight based on the tibromo compound,up to an amount equal in weight to the dibromo compound, although larger
. l, amounts can be used. The reaction commonly talces about one hour, after which
the compound of the formula II, wherein-R is hydrogen, is recovered simply
I by filtration followed by removal of the solvent in vacuo.
25 I 6,6-Dibromopenicillanic acid l~-oxide is prepared by oxidation of
6,6-dibromopenicillanic acid with 1 equivalent of 3-chloroperbenzoic acid in
tetrahydrofuran at 0-25~ C. for ca 1 hour, according to the procedure of
Harrison et al., Journal of the Chemical Societ~ (London) Perkin I, 1772 (1976)j.
6,6-Dibromopenicillanic acid is prepared by the method of Clayton, Journal of
the ~ S5.~ (London), (C) 2123 (1969).
,,.-. 1. .
1!
.... .
, . . . . . ~. ~.. ,
. ~ . ~ . . .-,
1119164 `~
Penicillanic acid l~-oxide, the compound of the formula III, wherein
Rl i6 hydrogen, can be prepared by controlled oxidation of peniclllanic acid.
~hus, it can be prepared by treating penicillanic acid with one molar equiva-
lent of 3-chloroperbenzoic acid in an inert solvent at about 0 C. for about
one hour. Typical solvents which can be used include chlorinated hydrocarbons,
such as chloroform and dichloromethane; ethers, such as diethyl ether and
tetrahydrofuran; and low molecular weight esters such as ethyl acetate and
butyl acetate. The product is recovered by conventional techniques.
Penicillanic acid is prepared as described in British patent No.
1,072,108.
Compounds of the formula II and III, wherein R is an ester-forming
residue readily hydrolyzable in vivo, can be prepared directly from the
compound of formula II or III, wherein Rl is hydrogen, by esterification,
using standard procedures. In the case wherein Rl is selected from the group
consisting of 3-phthalidyl, 4-crotonolactonyl, y-butyrolacton-4-yl and groups
of the formula X, and XI, wherein R3, R4 and R5 are as defined previously,
they can be prepared by alkylation of the appropriate compound of the
ormula II or III, wherein Rl is hydrogen, ~ith-a 3-phthalidyl halide,
4-crotonolactonyl halide, a y-butyrolacton-4-yl halide, or a compound of the
formula XII or XIII. The reaction is carried out in exactly the same manner
as described previously for esterification of penicillanic acid l,l-dioxide
Wlth a 3-phthalidyl halide, a 4-crotonolactonyl halide, a y-butyrolacton-4-yl
halide, or a compound of the formula XII or XIII.
_
~ ternatively, the compou=do of the for=ula Il, whereiD R ~s a:
ester-forming residue readily hydrolyzable in vivo, can be prepared by oxida-
tion of the appropriate ester of 6,6-dibromopenicillanic acid, followed by
debromination. The esters of 6,6-dibromopenicillanic acid are prepared from
6,6-dibromopenicillanic acid by standard methods. The oxidation is carried out,
for example, by oxidation with one molar equivalent of 3-chloroperbenzoic acid,
as described previously for the oxidation of 6,6-dibromopenicillanic acid to
6,6-dibromopenicillanic acid l~-oxide; and the debromination is carried out
as described previously for the debromination of 6,6-dibromopenicillanic acid
l-oxide.
In like manner, the compounds of the formula III, wherein Rl is an
ester-forming residue readily hydrolyzable in vivo can be prepared by
¦oxidation of the appropriate ester of penicillanic acid. The latter compounds
are readily prepared by esterification of penicillanic acid using standard
methods. The oxidation is carried out, for example, by oxidation with one
molar equivalent of 3-chloroperbenzoic acid, as described previously for
the oxidation of penicillanic acid to penicillanic acid l~-oxide.
The compounds of the formula II, wherein R is a carboxy protecting
group can be obtained in one of two ways. They can be obtained simply by
taking penicilIanic acid l~-oxide and at"aching a carboxy protecting group
thereto. Alternatively, they can be obtained by: (a) attaching a carboxy
protecting group to 6,6-dibromopenicillanic acid; (b) oxidizino the protected
- 12
~ l ~
6,6-dibromopenicillanic acid to a protected 6,6-dibromopenicillanic acid 1~-
oxide u6ing 1 molar equivalent of 3-chloroperbenzoic acid; and (c) debromina-
ting the protected 6,6-dibromopenicillanic acid l~-oxide by hydrogenolysis.
¦ The compounds of the formula III, wherein Rl is a carboxy protecting
group can be obtained simply by attaching a protecting group to penicillanic
acid l~-oxide. Alternatively, they can be obtained by: (a) attaching a car-
boxy protecting group to penicillanic acid; and (b)oxidizing the protected
penicillanic acid using 1 molar equivalent of 3-chloroperbenzoic acid as pre-
viou61y described. '
The compound~ of formulas I, II and III, wherein R is hydrogen, are
acidic and will form salts with ba6ic agents. Such salts are considered to
be within the scope of this invention. These 6alts can be prepared by standard
techniques, such as contacting the acidic and basic components, usually in a
1:1 molar ratio, in an aqueous, non-aqueous or partially aqueous medium, as
appropriate. They are then recovered by filtration, by precipitation with a
¦ non-601vent'followed by filtration, by evaporation of the solvent, or in the
¦¦ case of aqueous solutions, by lyophilization, as appropriate. Basic agent~
¦! which are 6uitably employed in salt formation belong to both the organic and
jl inorganic types, and they include ammonia, organic amines, alkali metal hy-
20 ¦ droxide~, car~onates, bicarbonates, hyd~ides and alkoxides, as well as alkaline
¦ earth metal hydroxides, carbonates, hydrides and alkoxides. Representative
¦ example6 of 6uch bases are primary amines, such as n-propylamine, n-butylamine,
aniline, cyclohexylamine, benzylamine.and octylamine; secondary
amine~, 6~ch'as diethylamine, morpholine, pyrrolidine and
25 ¦ piperidinei tertiary amines, such a6 triethylamine, N-
¦ ethylpiperidine, N-methylmorpholine and 1,S-diazabicyclo~4.3.0~non-5-ene; hy-
¦ droxides, ~uch as sodium hydroxide, potassium hydroxide, ammonium hydroxide
snd barium hydroxide; alkoxides, such' as ~odium ethoxide and pota6sium ethoxide ;
1119164
hydrides, such as calcium hydride and sodium hydride; carboDate~, such as po-
tassium carbonate and sodium carbonate; bicarbonates, such as sodium bicarbona
and potassium bicarbonate; and al~ali metal salts of long-chain fatty acids,
such as sodium 2-ethylhexanoate.
Preferred salts of the compounds of the formulas I, II and III are
sodium, potassium and triethylamine salts.
As indicated hereinbefore, the compounds of formula I, wherein R is
hydrogen or an ester-forming residue readily hydrolyzable ln vivo, are anti-
bacterial agents of medium potency. The in vitro activity of the compound
of the formula I, wherein R is hydrogen, can be demonstrated by measuring
its minimum inhibitory concentrations (MIC's) in mcg/ml against a variety of
microorganisms. Tlle procedure which is followed is the one recommended by
the International Collaborative Study on Antibiotic Sensitivity Testing
(Ericcson and Sherris, Acta. Patholo~ica et Microb ologia Scandinav, Supp.
217, Sections A and B: 1-90 [1~70]), and employs brain heart infusion
(BHI) agar and the inocula replicating device. Overnight growth tubes are
diluted 100 fold for use as the standard inoculum t20,000-10,000 cells in
approxi~ately 0.002 ml. are placed on the agar surface; 20 ml. of
BHI agar/dish). Twelve 2 fold dilutions of the test compound are employed,
with initial concentration of the test drug being 200 mcg./ml. Single
colonie6 are disregarded when reading plates &fter 18 hrs. at 37 C. The
susceptibility (MIC) of the test organism is accepted as the lowest concen-
tration o$ compound capable of producing complete inhibition of growth as
judged by the naked eye. MIC values for penicillanic acid l,l-dioxide
agalnst several microorganisms are shown in Table I.
- 14
'.;`
9~
.
TABLE I
In Vitro Antibacterial Activity of
Penicillanic Acid l.l-Dioxide
. . '' ' ''
_ Microorganism MIC (mc~./ml.)
Staphylococcus aureus 100
Streptococcus faecalis>200
Streptococcus pyogenes100
Escherichia coli 5V
` Pseudomonas aeruginoSa200
Xlebsiella pneumoniae 50
Proteus mirabilis 100
Proteus morgani 100
! Salmonella typhimurium50
¦, Pasteurella multocida 50
15 I Serratia marcescens 100
I Enterobacter aerogenes25
¦ Enterobacter clocae 100 ~`
¦ - Citrobacter freundii 50
Il Providencia 100
20 j Staphylococcus epitermis 200
Pseudomonas putida >200
I Hemophilus influenzae >50
,¦1 Neisseria gonorrhoeae0.312
I, .
-15-
.
~, -
I ~119~64
The compounds of the formula I, wherein Rl is hydrogen or an ester-
forming residue readily hydrolyzable in vivo, are active as antibacterial
agents in vivo. In determining such activity, acute experimental infections
¦ are produced in mice by the intraperitoneal inocùlation of the mice with a
1 standardized culture of the test organism suspended in 5 percent hog gastric
l mucin. Infection severity is standardized so that the mice receive one to ten
- ~ ¦ times the LDloo dose of the organism (LDloo: the minimum inoculum of organism
¦ required to consistently kill 100 percent of the infected, non-treated control
mice). The test compound is administered to the infected mice using a
multiple dosage regimen. At the end of the test, the activity of a compound
is assessed by counting the number of survivors among the treated animals and
expressing the activity of a compound as the percentage of animals which sur-
vive.
The in vitro antibacterial activity of the compound of the formula I
wherein R is hydrogen makes it useful as an industrial antimicrobial, for
example in water treatment, slime control, paint preservation and wood
preservation, as well as for topical application as a disinfectant. In the
case of use of this compound for topical application, it is often convenient
to admix the active ingredient with a non-toxic carrier, such as vegetable or
,- 20 mineral oil or an emollient cream. Similarly, it can be dissolved or
dispersed in liquid diluents or solvents such as water, alkanols, glycols or
mixtures thereof. In st instances it is appropriate to employ concentrations
of the active ingredient of from about 0.1 percent to about 10 percent by
weight, based on total compositian.
The in vivo activity of the compounds of formula I, wherein Rl
is hydrogen or an ester-forming-residue readily hydrolyzable in vivo, makes
them suitable for the control of bacterial infections in mammals, including
man, by both the oral and parenteral modes of administration. The compounds
J~,~iJ; will find use in the control of infections caused by susceptible bacteria
,3~ 30 in buman sub~ects, e.g. infections caused by strains of Neisseria gonorrhoeae.
~: ~?~,,
~.", i `' - ", , -~
` ~ , 1119164
¦ ~hen conslderlng therapeutic o~e of a co=pound o~ the or==1- 1, or
a salt thereof, in a mammal, particularly man, the compound can be administered
alone, or it can be mixet with pharmaceutically acceptable carriers or diluents
Ihey can be administered orally or parenterally, i.e. intramuscularly, sub-
cutaneously or intraperitoneally. The carrier or diluent is chosen on the
basis of the intendet mode of administration. ~or example, when considering
the oral mode of administration, an antibacterial penam cempound of this in-
vencion can be used in the form of tablets, capsules, lozenges, troches, powderg,
syrups, ellxiss, aqueous solutions and suspensions, and the like, in accordance
with standard pharmaceutical practice. The proportional ratio of active in-
gredient to earrier will naturally depend on the chemieal nature, solubility
and stability of the aetive ingredient, as well as the dosage contemplated.
~owever, pharmaceutical compositions eontaining an antibacterial agent of tbe
formula I will likely contain from about 20Zto about 95% of active ingredient.
In the ease of tabiets for oral use, earriers which are com~only used include
laetose, sodium citrate and salts of phosphoric acid. Various disintegrants
! such as starch, and lubricatlng agents, such as magnesium stearate, sodium
lauryl sulfate and talc, are commonly used in tablets. For oral administration
ll in eapsule form, useful diluents are lactose ant high molecular wei~ht poly-
20 1l ethylene glycols. When aqueous suspensions are required for oral use, theactive ingredient is combined wlth emuls,ifying and suspending agencs. If
teslred, certain 8weetening and/or flavorin~ agents can be added. ~or paren-
eeral atministration, which includes intramuscular, intraperitoneal, sub-
eutaneous and intravenous u6e, sterile solutions of the active lngredient
25 are u~ually prepared, and the pH of the solutions are 6uitably adjusted and
buffered. For intravenous use, the total eoncentation of solutes should be
controlled to render the preparation ~so~onie.
-17-
1119164
!
., I
- As lndicated earlier, the antibacterial agents of thi6 invention are
of u6e in human subject6 again6t 6u6ceptible Organi8ms. The prescribing
physician will ultimately determine the appropria~e dose for a given human
6ubject, and thi6 can be expected to Vary according to the age, weight~
and respon6e of the individu~l patient~ a6 well as the nature and the severity
of the patient'6 6ymptoms. The compound6 of this invention will normally be
u8ed orally at do3age~ in the range from about lO to about 200 mg. per kilogra
of body weight per day, and parenterally at dosage6 from about 10 to about
400 mg. per"kilogram of body weight per day. These figures are illu6trative
I only~ however~ and in some ca6e6 it may be neCessary to use dosages outside
these limits.
However, as indicated hereinbefore, the compounds of the formula I,
wherein R is hydrogen or an ester-forming residue readily hydrolyzable in vivo,
are potent inhibitor6 of microbial ~-iactanà6e6, and they increase the anti-
bacterial effectiveness of ~-lactam antibiotic6 (penicillin6 and cephalosporin~)
agaln8t many microorganism6, particularly those whiCh produce a B-lactam.~qe.
The manner in which the said compounds of the formula I increase the effective~
ne8s of a ~-lactam antibiotic can be appreciated by reference to exp-:-;imonts i~
i! whiCh the MIC of a given antibiotic alone~ and a compound of the formula I
¦ alone~ are measured. The6e MIC's are then compared with the MIC values
obtained with a combination of the given antibiotic and the compound of the
formula I. When the antibacterial potency of the combination is significantly
greater than would have been predicted from the potencies of the individual
ompound8, thi8 is considered to constitute enhancement of activity. The MIC
values of combinations are measured u6ing the method de6cribed by Barry and
Sabath in "Manual of Clinical Microbiology", edited by Lenette, Spaulding
and Truant~ 2nd edition, 1974~ American Society for Micrnbiology.
.
Ii
1916
¦ Results of experiments illuserating that penicillanic acit 1,1-
¦ dioxide enhances the effectiveness of ampicillin are reported in ~able II.
From Table II, it can be seen that against 19 ampicillin-resistant strains
of SaEhyl~coccus aur_~s, the mote ~IC of ampicillin, and of penicillanic acid
l,l-dioxide, is 200 mcg./ml. Howèver, the mode MIC's of ampicillin and peni-
cillanic acid l,l-dioxide in combination are 1.56 and 3.12 mcg./ml.,
respectively. Looked at another way, this means that whereas ampicillin alone
has a mode MIC of 200 mcg.lml. against the 19 strains of StaPhylococcus .
aureus, its mode ~IC is reducet to 1;56 mcg./ml. in the presence of 3.12 mcg./
o~ penic~llanic acid l,l-dioxide. The other entries in Table II show enhance-
ment of the antibacterial effectiveness of ampicillin against 26 ampicillin
i resistant stra~ns of HaemoDhilus influenzae, 18 ampiciilin resistant strains
of Klebsiella Dneumoniae and 15 6trains of the anerobe Baceeroides fra~ilis.
¦ Tables III, IV and V 6how enhancement of the antibacterial potency of benzyl-
penicillin (penicillin G) carbenicillin (~-carboxybenzylpenicillin) and
cefazolin, respectively, against strains of S. aureus, H. influenzae,
~- e~ d -c~r~
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The compounds of ~he for~ula I, wherein R is hydrogen or an ester-
forming residue readily hydrolyzable in ~ enhance the antibacterial ef-
fectiveness of ~-lactam antibiotics in vivo. This is, they lower the amount
of the antibiotic which is needed to protect mice against an otherwise lethal
inoculum of certain ~-lacta s se producing bacteria.
The ability of the compounds of the formula I, wherein R is hydroge
or an ester-forming residue readily hydrolyzable in vivo, to enhance the
effectiveness of a B-lactam antibiotic~against B-lactamase-producing bacteria
makes them valuable for co-administration with ~-lactam antibiotics in the
treatment of bacterial iafections in mammals, particularly man. In the treat-
ment of a bacterial infection, the said compound of the formula I can be
comingled with the ~-lactam antibiotic, and the two agents thereby administere
6imultaneously. Alternatively, the said compound of the formula I can be
administered as a separate agent during a course of trea~ment with a ~-lactam
antibiotic. In some instances it will be advantageous to pre-dose the subject
with the compound of the formula I before initiating treatment with a B-lactam
antibiotic.
When using penicillanic acid l,l-dioxide or an ester thereof readily
hydrolyzable in vivo to enhance the effectiveness of ~-lactam antibiotic, it is
administered preferably in formulation with standard pharmaceutical carriers
or diluents. The methods of formulation discussed earlier for use of penicil-
lanic acid l,l-dioxide or an ester thereof readily hydrolyzable in vivo as a
6ingle-entity antibacterial agent can be used when co-administration with
another ~-lactam antibiotic is intended. A pharmaceutical composition com-
pri~ing a pharmaceutically-acceptable carrier, a ~-lactam antibiotic and
penicillanic acid l,l-dioxide or a readily hydrolyzable ester thereof will
normally contain from abo~t 5 to about 80 percent of the pharmaceutically
acceptable carrier by weight.
When using penicillanic acid l,l-dioxide or an ester thereof readily
hydrolyzable in vivo in combination with another B-lactam antibiotic, the
sulfone can be administered orally or parenterally, i.e. intramuscularly, sub-
cutaneou~ly or intraperitoneally. Although the prescribing physician will
- 24 -
. , ,
` ` .
1119~64
.
ultimately decide the do~age to be used in a human subject, the ratio of
the daily dosages o~ the penicillanic acid l,l-dioxide or ester thereof and
the ~-lactam antibiotic will normally be in the range from about 1:3 to 3:1.
Additionally, when using penicillanic acid l,l-dioxide or an ester thereof
readily hydrolyzable in vivo in combination with another ~-lactam antibiotic,
the daily oral dosage of each component will normally be in the range from abo~ t
10 to about 200 mg. per kilogram of body wei~ht and the daily parenteral
dosage of each component will normally be about 10 to about 400 mg. per kilo-
gram of body weight. These figures are illustrative only, however, and in
come cases it nay be nece~ary to use dosages outside these limits.
Typical B-lactam antibiotics with which penicillanic acid l,l-dioxid
and its esters readily hydrolyzable in vivo can be co-administered are:
6-(2-phenylacetamido)penicil~anic acid,
6-(2-phenoxyacetamido)penicillanic acid, -
6-(2-phenylpropionamido)penicillanic acid,
6-(D-2-aniino-2-phenylacetamido)penicillanic acid,
6-(D-2-amino-2-[4-hydroxyphenyl~acetamido)penicillanic acid,
6-(D-2-amino-2-[1,4-cyclohexadienyl~acetamido)penicillanic acid,
6-(1-aminocyclohexanecarboxamido)penicillanic acid,
6-(2-carboxy-2-phenylacetamido)penicillanic acid,
6-(2-carboxy-2-E3-thienyl]acetamido)penicillanic ?cid,
6-(D-2-[4-ethylpiperazin-2,3-dione-1-carboxamido~-2-phenylacetamido)penicil-
lanic acid,
6-(D-2-[4-hydroxy-1,5-naphthyridine-3-carboxamido]-2-pllenylacetamido)-
penlcillanic acid,
6-(p-2-s~lfo-2-phenylacetamido)penicillanic acid,
6-(D-2-sulfoamino-2-phenylacetamido)penici}lanic acid,
6-(D-2-[imldazolidin-2-one-1-carboxamido]-2-phenylacetamido)penicillanic acid,
6-(D-[3-methylsulfonylimidazolidin-2-one-1-carboxamido]-2-phenylacetamido)-
penicillanic acid,
6-([hexahydro-lH-azepin-l-yl]methyleneamino)penicillanic acid,
.. , . , . . ~,,, ~ .,
' :,- ~
:
11191~i4
~¦ acetoxymethyl 6-(2-phenylacetamido)peniclllanate,
acetoxymethyl 6-(D-2-amdno-2-phenylacetamido)penicillanate,
acetoxymethyl 6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)penicillanate,
pivaloyloxymethyl 6-(2-phenylacetamido)penicillanate, .
S pivaloyloxymethyl 6-(D-2-amino-2-phenylacetamido)penicillanate,
pivaloyloxymethyl 6-(D-2-amino-2-14-hydroxyphenyl]acetamido)penicillanate,
l-(ethoxycarbonyloxy)ethyl 6-(2-phenylacetamido)penicillanate, ¦
¦1 l-(ethoxycarbonyloxy)ethyl 6-(D-2-amino-2-phenylacetamido)penicillanate,
I l-(ethoxycarbonyloxy)ethyl 6-(D-2-amino-2-[4-hydroxyphenyllacetamido)-
10 ¦ penicillanate, ~ -
3-phthalidyl 6-(2-phenylacetamido)penicillanate,
3-phthalidyl 6-(D-2-amino-2-phenylacetamido)penicillanate, - .,
Il 3-phthalidyl 6-(D-2-amino-2-[4-hydroxyphenyl]acetamido)penicillanate, ¦
j'l 6-(2-phenoxycarbonyl-2-phenylacetamido)penicillanic acid, j i,
15 li 6-~2-tolyloxycarbonyl-2-phenylacetamido)penicillanic:acid,
6-~2-~5-indanyloxycarbonyl]-2-phenylacetamido)penicillanic acit,
j 6-(2-phenoxycarbonyl-2-13-thienyl~acetamido)penicillanic acid, t
6-(2-tolyloxycarbonyl-2-[3-thienyl]acetamido)penicillanic acid, ¦
¦ 6-(2-[5-indanyloxycarbonyl~-2-~3-thienyl]acetamido)penicillanic acid,
20 !1 6-(2,2-dimethyl-5-oxD-4-phenyl-1-imidazolidinyl?penicillanic acid,
7-(2-[2-thienyl]acetamido)cephalosporanic acid, . I
7-(2-[1-tetrazolyl~acetamido-3-(2-[5-methyl-1,3,4-thiadiazolyl]thiomethyl)-3- ..
¦ desacetoxymethylcephalosporanic acid, ¦ ;
7-(D-2-amino-2-phenylacetamido)desacetoxycephalosporanic acid,
7--methoxy-7-(2-[2-thienyl~acetamido)-3-carbamoyloxymethyl-3-desacetoxymethyl
cephalosporanlc acid,
7-~2-cyanoacetamido)cephalosporanic acid,
7-(D-2-hydroxy-2-phenylacetamido)-3-(5-[l-methyltetrazolyl]tbiomethyl)-3-
de~acetoxymethylcepbalosporanic acid,
7-(2-[4-pyridylthio~acetamido)cephalosporanic acid,
7-(D-2-a~ino-2-[1,4-cyclohexadienyl]acetamidojcephalosporanic acid,
. ¦ 7_ ~e-2-amino-2-phenylacetamldo)cephalosporanic acid, and
the pharmaceutically-acceptable salts thereof.
- 26 ~
.
. : .
~1119164
As will be appreciated by one skilled in the art, some of the above
~-lactam compounds are effective when administered orally or parenterally,
while others ar~ effective only when administered by the parenteral route.
IWhen penicillanic acid l,l-dioxide or an ester thereof readily hydrolyzable
in vivo is to be used simultaneously (i.e. co-mingled) with a ~-lactam anti-
biotic which is effective only on parenteral administration, a combination r
formulation suitable for parenteral use will be required. When the penicillanic
acid l,l-dioxide or ester thereof is to be used simultaneously (co-mingled)
with a ~-lactam antibiotic which is effective orally or parenterally, combina- -'
tions suitable for either oral or parenteral administration can be prepared.
Additionally, it is possible to administer preparations o ~hc penicillanic
acid l,l-dioxide or ester thereof orally, while at the same time administering
further ~-lactam antibiotic parenterally; and it is also possible to
lladminister preparations of the penicillanic àcid l,l-dioxide or ester
~hereof parenterally, while at the same time administering the further ~-
~actam antibiotic orally.
The following examples are provided solely for the purpose of further
hllustration. Infrared (IR) spectra were measured as potassium bromide discs
B KBr discs) or as Nujol~mulls, and diagnostic absorption bands are reported in
ave numbers (cm ). Nuclear magnetic resonance spectra (NMR) were measured
t 60 MHz for solution6 in deuterochloroform (CDCi3), perdeutero dimethyl sul-
foxide (DMSO-d6) or deuterium oxide (D20), and peak positions are expressed in
arts per million (ppm) downfield from tetramethylsilane or sodium 2,2-
imethyl-2-silapentane-S-sulfonate. The following abbreviations for peak
hapes are used: ~, singlet; d, dbublet; t, triplet; q, quartet, m, multiplet.
3~ ,, ,
TraJ~n1 a r k
111916g
EX~PL~ 1
Penicillanic Acid l,l-Dioxide
To a solution of 6.51 g. (41 mmole) of potassium permanganate
I in 130 ml. of water and 4.95 ml. of glacial acetic acid, cooled to ca. 5 C.,
5 ¦ was added a cold (ca. 5 C.) solution of 4.5B g. (21 mmole) of the sodium
salt of penicillanic acid in 50 ml. of water. The mixture was stirred at ca.
5 C. for 20 minutes and then the cooling bath was removed. Solid sodium
i bisulfite was added until the color of the potassium permanganate had been
discharged, and then the mixture was filtered. To the aqueous filtrate - '
was added half its volume of saturated sodium chloride solution, and then
the pI~ was adjusted to 1.7. The acidic solution was extracted with ethyl
acetate. The extracts were dried, and then evaporated in vacuo, to give
3.47 g. of the title product. The aqueous mother liquor was saturated with
¦ sodium chloride, and further extracted with ethyl acetate. The ethyl acetate
solution was dried and evaporated ln vacuo, to give a further 0.28 g. of
i product. The total yield was therefore 3.75 g. ~78Z yield). The ~IR spectrum
I (D~O-d6) of the product showed absorptions at 1.40 (s,3H)J 1.50 (s,3H)~
3.13 (d of d's, lH, Jl ~ 16Hz, J2 ~ 2~z), 3.63 (d of d's~ 1~, Jl D 16 Hz,
~! J2 ' 4Uz), 4..2 (s, lU) a~d 5.03 (d of d~s, lU, JI = 4Uz, J2 ~ Z~Z) ppm.
1~ ' ' ' ,~
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,19~64
EXA~IPLE 2 !!
¦ Benzyl Penicillanate l,l-Dioxide ¦
¦ To à stirred solution of 6.85 g. (24 mmole) of benzyl penicillanate
¦¦ in 75 ml; of ethanol-free chloroform, urder nitrogen, in an ice-bath, was
¦1 added in two portions, several minutes apart, 4.78 g. of 85% pure 3-chloro- It
¦I perbenzoic acid. Stirring was continued for 30 minutes in the ice-bath, .-
and then for 45 minutes without external cooling. The reaction mixture was ll
washed with aqueous alkali (pH 8.5), followed by saturated sodium chloride, ~ Ii
and then it was dried and evaporated in vacuo to give 7.05 g. of residue. ¦
10 Examination of this residue showed it to be a 5.5:1 mixture of benzyl penicil- ¦
¦ lanate l-oxide and benzyl penicillanate l,l-dioxide.
To a stirred solution of 4.85 g. of the above 5.5:1 sulfoxide-
l¦ sulfone mixture in 50 ml. of ethanol-free ch~loroform, under nitro~en, was
¦¦ added 3.2 g. of 85% pure 3-chloroperbenzoic acid at room temperature. The
15 l¦ reaction mixture was stirred for 2.5 hours, and then it was diluted with
~¦ ethyl acetate. The re~ultant mlxture was added to water at pH 8.0, and then
the layers were separated. The or~anic phase was washed with water at pH 8.0,
¦ followed by saturated sodium chloride, and then it was dried using sodium
J .sulfate. Evaporation of the solvent in vacuo afforded 3.59 g. of the title
20 ¦~ compound. The N~iR spectrum of the produot (in CDC13) showed absorptions at
¦¦ 1.28 (6, 3H), 1.58 (s,3H), 3.42 (m,211), 4.37 (s,lH), 4,55 (m,lH), 5.18 J
l~ (q,2H, J ~ 12 Hz) and 7.35 (s,5H) ppm. .
. ~1 , - , ,. . ~
_29
Il .,' ;
11~9164
EXAMPLE 3 .
Penicillanic Acid l.l-Dioxide
To a stirred solution of 8.27 g. of benzyl penicillanate 1,1-
dioxide in a mixture of 40 ml. of methanol and 10 ~1. of ethyl acetate was
5 slowly added 10 ml. of water, followed by 12 g. of 5% palladium-on-calcium
carbonate. The mixture was shaken under an atmosphere of hydrogen, at r
52 psi, for 40 minutes, and then it was filtered through supercel (a
diatomaceous earth). The filter cake was washed with methanol, and with
agueous methanol, and the washings were added to the filtrate. The combined
10 solution was evaporated in vacuo to remove the ma~or$ty of the organic
solvents and then the residue was partitioned between ethyl acetate and water
I at a pH of 2.8. The ethyl acetate layer was r~moved and the aqueous phase
! was further extracted with ethyl acetate. ~le combined ethyl acetate solutlonsl were washed with saturated sodium chloride solut$on, dried using sodium sul-
15 fate and then evaporated in vacuo. The residue was slurried in a 1:2 ~ixture
. _
of ethyl acetate-ether, to ~lve 2037 g. of the tltle product havinP. a melting
point of 148-51 C. The ethyl acetate-ether mixture was evaporated giving a
further 2.17 g oE producc.
,,
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1.
9164
Il . ',
¦ EXA~LE 4
Pivaloyloxymethyl Penicillanate -
1 l-Dioxide .
. ' ' . .'
I To 0.615 g. (2. 41 mmole? of penicillanic acid l,l-dioxide in
2 ml. of N,N-dimethylformamide was added 0.215 g. t2.50 mmole) of diiso-
propylethylamine followed by 0.365 ml. of chloromethyl pivalate. The reaction
mixture was stirred at roo~ temperature for 24 hours, and then it was diluted
with ethyl acetate.and water. The ethyl acetate layer was separated and
~ washed three times with water and once with saturated sodium chloride solution.
The ethyl acetate solution was then drled using anhydrous sodiu~ sulfate~
¦ and evaporated in vacuo to give 0.700 g. of the title product as a solid,
I mp 103-4 C. The N~R spectrum of the product (in CDC13) showed absorptions
¦ at 1.27 (s, 9H), 1.47 (s, 3H), 1.62 (s, 3H), 3.52 (m, 2H), 4.47 (s, lH),
¦¦ 4.70 (m, lH), 5.73 (d, lH, J - 6.0 Hz) and 5.98 (d, lH, J - 6.0 Hz).
15 ¦¦ EXAMPLE 5 ! .
The procedure of Example 4 is repeated, except that the pivaloyoxy-
¦ methyl chloride used therein is replaced by an equimolar amount of acetoxy-
I methyl chloride propionyloxymethyl chloride and hexanoyloxymethyl chloride, .-
.¦ respectively, to give:
acetoxymethyl'penicillanate l,l-dioxide,
.j propionyloxymethyl penicillanate l,l-dioxide and
hexanoyloxymethyl penicil~lanate l,l-dioxide,
renpectively. : ¦
_ 31 _
3l119~
EXIu'~E 6
3-Phthalidyl Penicillanate
l,l-Dioxide
¦ To 0.783 g. (3.36 mmole) of penicillanic acid l,l-dioxide in 5 ml.
of N,N-dimethylformamlde was added 0.47 ml. of triethylamine followed by
0.715 g. of 3-bromophthalide. The reaction mlxture was stirred for 2 hours
at room temperature and then it was diluted with ethyl acetate and water.
The pH of the aqueous phase was raised to 7.0 and the layers were separated.
l The ethyl acetate layer was washed successively with water and saturated
10 ¦ sodium chloride solution, and then it was dried using sodium sulfate. The
¦ ethyl acetate solution was evaporated in vacuo leaving the title product as
a white foam. The NMR spectrum of the product (in CDC13) showed absorpCions
at 1.47 (s, 6H), 3.43 (m, lH), 4.45 (s, lH), 4.62 (m, lH~, 7.40 and
l 7.47 (26's, lH) and 7.73 (m, 4H) ppm '
15 ¦ When the above procedure is repeated, except that the 3-bromophthalid
i6 replaced b!y 4-bromocrotonolactone and 4-bro~o-y- -
butyrolactone, respectlvely, this affords: !
4-crotonolactonyl penicillanate l,l-dioxide.and
. I ~-butyrolacton-4-yl penicillanate,
20 ¦ respect~ve y.~
'11 ' .
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- 32. - ~
1119164
EXAMPLE 7
l-(Ethoxycarbonyloxy)ethyl Penicillanate l,l-Dioxide
A mixture of 0.654 g. of penicillanic acid l,l-dioxide, 0.42 ml.
of triethylamine, 0.412 g. of l-chloroethyl ethyl carbonate, 0.300 g. of
sodium bromide and 3 ml. of N,N-dimethylformamide was stirred at room
temperature for 6 days. ;It was then worked up by diluting it with ethyl
acetate and water, and then the pH was adjusted to 8.5. The et~yl acetate
layer was separated, washed three times with water, washed once with saturated
sodium chloride, and then it was dried using anhydrous sodium sulfate. The
ethyl acetate was removed by evaporation in vacuo leaving 0.390 g. of the title
product as an oil.
The above product was combined with an approximately equal amount
of similar material from a similar experiment. The combined product was
dissolved in chloroform and 1 ml. of pyridine was added. The mixture was
stirred at room temperature overnight and then the chloroform was removed by
evaporation in vacuo. The residue was partitioned between ethyl acetate and
water at pH 8~ The separated and dried ethyl acetate was then evaporated
in vacuo to give 150 mg. of the title product (yield ca 7%). The IR spectrum
(film) of the product showed absorptions at 1805 and 1763 cm . The NMR
spectrum (CDC13) showed absorptions at 1.43 (m, 12H), 3.47 (m, 2H), 3.9
(q, 2H, J = 7.5 Hz), 4.37/m, lH), 4.63 (m, lH) and 6.77 (m, lH) ppm.
ll l
:1.119164
~LE 8 ¦ ~
¦~he procedure o~ Example 7 is repeated, except that the l-chloroethy~ j
ethyl.carbonate is replaced by an equimolar amount of the appropriate 1-
, chloroalkyl alkyl carbonate, l-(alki~noyloxy~ethyl chloride or l-methyl-l-
5 1 (alkanoyloxy)ethyl chloride, to produce the following compounds:
methoxycarbonyloxymethyl penicillanate l,l-dioxide,
ethoxycarbonyloxymethyl penicillanate .l,l-dioxide,
isobutoxycarbonyloxymethyl penicillanate l,l-dioxide,
l-(methoxycarbonyloxy)ethyl penicillanate l,l-tioxide,
10 1 l-(butoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
¦l l-(acetoxy)ethyl penicillanate l,l-dioxide, .
~ (butyryloxy)ethyl penicillanate l,l-dioxide,
¦¦ l-(pivaloyloxy)ethyl penicillanate l,l-dioxide,
~ (hexanoyloxy)ethyl penicillanate l,l-dioxide, !_ ¦
¦ l-methyl-l-(acetoxy)ethyl penicillanate l,l-dioxide and
l-methyl-l-(isobutyryloxy)ethyl penicillanate l,l-dioxide, ¦ ;
! respectively. I
: ' .
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1119~6~
XA~LE 9
¦ The procedure of Example 4 ls repeated, except that the chloromethyl
pivalate is re?laced by an equimolar amount of benzyl bromide ant 4-nitrobenzy L
bromide, respectively, to produce benzyl penicillanate l,l-dioxide and 4_nitro
benzyl penicillanate l,l-dioxide, respectively.
EXA~LE 10
Penicillanic Acid l~-Oxide
Io 1~4 g. of prehydrogenated 5~ palladium-on-calcium carbo~ate in
l 50 ml. of water was added a solution of 1.39 g. of benzyl 6,6-dibromopenicilla .
10 ¦ nate l~-oxide in 50 ml. of tetrahydrofuran. The ~ixture was shaken under an
¦ atmosphere of hydrogen at ca. 45 p.s.i. and 25 C. for 1 hour, and then it was ~,
filtered. The filtrate was evaporated in vacuo to remove the bulk of the
¦ tetrahydrofuran, and then the aqueous phase was extracted with ether. The
¦ ether extracts were evaporated in vacuo to give 0.5 g. of material which ap-
peared to be largely benzyl penicillanate l~-oxide.
The above benzyl penicillanate l~-oxide was combined with a further
¦¦ 2.0 g. of benzyl 6,6-tibromopenicillanate l~-oxide and dissolved in 50 ml. of
¦ tetrahydrofuran. The solution was added to 4.0 g. of 5% palladium-on-calcium
.1 carbonate, in 50 ml. of water, and the res~ltin~ mixture was shaken under
20 ! an atmosphere of hydrogen, at ca. 45 p,s.i. and 25C. overnight. The mixture
¦ was flltered, and the filtrate was extracted with ether. Ihe extracts were
evaporated in vacuo, and the residue was purified by chro~atog s phy on silica ¦ ;
gel, eluting with chloroform. This afforded 0.50 g. of material.
The latter material was hydrogenated at ca. 45 p.s.i. at 25 C.
1n water-methanol (1:1) with 0.50 g. of 5% palladium-on-calcium carbonate for
¦ 2 hours. At this point, an additional 0.50 g. of SZ palladium-on-calcium car-
bonate was adted and the hydrogenatlon was continued at 45 p.s.i. and 25C.
' '''' '` ' . ~,
1~ .
~1 - 35 -
~1.119164
overnigh~. The reac~ion =i~ore was fil~ered, ex~rac~ed ~i~h e~her and che ex-
tracts were discarded. The residual aqueous phase was adjusted to pH 1.5 and
then extracted with ethjl acetate. The ethyl acetate extracts were dricd
(~a2SO4) and then evaporated in vacuo ~o give 0.14 g. of penicillanic acid
¦l-oxide. The NMR spectrum (CDC13/3MSO-d6~ showed absorptions at 1.4 (s, 3H),
¦1.64 (s, 3H), 3.60 (m, 2H), 4.3 (s, lH) and 4.54 (m, lH)ppm. The IR spectrum -
of the product (KBr disc~ showed absorptlons at 1795 and 1745 cm l.
EX~U~LE 11
. . !~
Penicillanic Acid l~-Oxide -
10 ¦ Io 1.0 g. of prehydrogenated 5% palladium-on-calcium carbonate in
¦30 ~1. of water is added a solution of l.O g. of 6,6-dibromopenicillanic acid
jl~-oxide. The mixture is shaken under an atmosphere of hydrogen, at ca. 45
!j p.s.i. and 25C., for l hour. The reaction mixture is then-filtered and the '
l filtrate is concentrated in vacuo to remove the methanol. The residual -aqueous
15 jphase is diluted with an equal volume of water, adjusted to pH 7, and washed
l¦with ether. The aqueous phase is then acidified to pH 2 with dilute hydro-
¦Ichloric acid and extracted with ethyl acetate. The ethyl acetate extracts are
¦¦dried (Na2SO4) and evaporated in vacuo to give pe icillanic acid l-oxide.
~1 ' ' ' ' . ':;
,~
l - 36 -
~,,
64 ~ i
EXA~PLE lZ
Penicillanic Acid_18-Oxide
. .
To a stirred soiution oE 2.65 g. tl2.7 mmole) of penicillanic acid in
¦ chloroform at 0C. was added 2.58 g. of 85% pure 3-chloroperbenzoic acit. I
After 1 hour, the reaction mixture was filtered and the filtrate was evaporated ¦ i
in vacuo. The residue was dissolved in a small amount of chloroform. The
solution was concentrated slowly until a precipitate be~an to appear. At this
point the evaporation was stopped and the mixture was diluted with ether. The
precipitate was removed by filtration, washed with ether and dried, to give
0.615 g. of penicillanic acid 18-oxide, m.p. 140-3C. The IR spectrum of the
product (CHC13 solution) showed absorptions at 1775 and 1720 cm 1 The N~
¦Ispectrum (CDC13/DMSO-d6) showed absorptions at 1.35 (s, 3H), 1.76 (s, 3H), 3.36
¦¦(m, 2H), 4.50 (~, lH) and 5.05 (m, lH~ppm. ~rom the NMR spectrum, the product
l¦appeared to be ca. 90% pure. ~
lS I Examination of the chloroform-ether mother liquor revealed that it
contained further penicillanic acid 18-oxide, and also some penicillanic acid
l~-oxJde.
Il , , .. i.
. I .~
~L119164
; EXAMPLE 13 .
¦ Esteri~ication of penicillanic acid l~-oxide or penicillanic acid
¦lB-oxide, as appropriate, with the requisite alkanoyloxy chloride, according to
Example 5, provides the following compounds: 1.
S acetoxymethyl penicillanate l-oxide,
propionyloxymethyl penicillanate l~-oxide,
pivaloyoxymethyl penicillanate l-oxide,
acetoxymethyl penicillanate l~-oxide,
propionyloxymethyl penicillanate l~-oxide ant
pivaloyloxymethyl penicillanate lB-oxide,
respectively.
1~ E.YAMPLE 14
¦ Reactlon of penicillanic acid la-oxide or penicillanic acid lB-oxide
with 3-bromophthalide, 4-bromocrotonolactone or 4-bro -y-butyrolactone,
a~ appropriate, affords the following compound~:
¦¦ 3-phthalidyl penicillanate l~-oxide
¦1 4-crotonolactonyl penicillanate l-oxide,
3-phthalidyl penicillanate l~-oxide,
¦1 4-crotonolactonyl penlcillanate l~-oxide and
20 !I y-butyrolacton-4-yl penicillanate l~-oxide,
respectlvely.
., I . , . ,,,
l ~ .
i . EXAM~L~ 15 .,
Reaction of penicillanic acid l-oxide or penicillanic acid 13-oxide,
as appropriate, with the requisite l-chloroalkyl alkyl carbonate or l-(alkanoyl-
l oxy)ethyl chloride, according to the procedure of ~xample 7, provides the fol-
lowing compounds:
¦ l-(ethoxycarbonyloxy)ethyl penicillanate l-oxide,
¦ methoxycarbonyloxymethyl penicillanate l~-oxide,
¦ ethoxycarbonyloxymethyl penicillanate l-oxide,
l isobutoxycarbonyloxymethyl penicillanate l~-oxide, .
lO ¦ l-(methoxycarbonyloxy)ethyl penicillanate l~-oxide, . I
¦ l-(butoxycarbonyloxy)ethyl penicillanate l~-oxide,
: ¦ l-(acetoxy)ethyl penicillanate l~-oxide,
l-(butyryloxy)ethyl penicillanate l~-oxide,`
¦ l-(pivaloyloxy)ethyl penicillanate l~-oxide, ~
15 ¦¦ l-(ethoxycarbonyloxy)ethyl penicillanate lB-oxide,
I m-thoxycarbonyloxymethyl penicillanate lB-oxide,
¦ ethoxycarbonyloxymethyl penicillanate lB-oxide,
. isobutoxycarbonyloxymetnyl penicillanaee lB-oxide,
l l-(methoxycarbonyloxy)ethyl penicillanate lB-oxide,
20 ¦ l-(butoxycarbonyloxy)ethyl penicillante'l~-oxide,
l-(acetoxy)ethyl penicillanate lB-oxite,
¦ l-(butyryloxy)ethyl penicillanate lB-oxide and
¦ l-(pivaloyloxy)ethyl penicillanate lB-oxide,
respectively. `
~ 39~
I EXAMPLE 16 .
¦ Reaction of penicillanic acid l~-oxide and penicillanic acid lB-oxide
with benzyl bromide, according to the procedure of Example 4, produces benzyl
penicillanate l~-oxide and benzyl penicillanate lB-oxide, respectively.
¦ In like manner, reaction of penicillanic acid l~-oxide and penicillanic
¦acid lB-oxide with 4-nitrobenzyl bromide, according to the procedure of ~xample
4, produces 4-nitrobenzyl penicillanate ll_oxide and 4-nitrobenzyl penicillanate
lB-oxide, respectively.
I EXA~MPLE 17
! Penicillanic Acid l,l-Dloxide
To 2.17 g. (10 mmole) of penicillanic acid l~-oxide in 30 ml. of
¦ethanol-free chloroform at ca. 0C. is added 1.73 g. (10 mmole) of 3-~hloroper-
¦benzoic acid. The mixture i9 stirred for l hour at ca. 0C. and then for an
,ladditional 24 hours at Z5~C. The filtered reaction mixture is evaporated in
15 livacuo to give penicillanic acid l,l-dioxide.
il
. .
,;: , .
i
EX~IPLE 18
. The procedure of Example 17 i6 repeated, except that the penicillanic t
¦acid l-oxide used therein is replaced by:
I . ,,
¦penicillanic acid lB-oxide,
5 1 acetoxymeehyl penicillanate la-oxide, }
¦propionyloxymethyl penicillanate la-oxide, -
pivaloyoxymethyl penicillanate la-oxide,
¦acetoxymethyl penicillanate lB-oxide,-
¦propionyloxymethyl penicillanate lB-oxide, -
10 ¦pivaloyloxymethyl penicillanate lB-oxide,
¦3-phthalidyl penicillanate la-oxide,
I3-phthalidyl penicillanate lB-oxide,
¦¦l-(ethoxycarbonyloxy)ethyl penicillanate la~oxide, !
¦¦~ethoxycarbonyIoxymethyl penicillanate l-oxide,
151~ethoxycarbonyloxymethyl penicillanate l-oxide,
, iaobutoxycarbonyloxymethyl penicillanate l-oxide,
¦ l-(methoxycarbonyloxy)ethyl penicillanate l-oxide,
I l-(butoxycarbonyloxy)ethyl penicillanate l-oxide,
.1 l-~acetoxy)ethyl penicillanate l-oxide,
20!I l-(butyryloxy)ethyl penicillanate l-oxi'de,
¦ l-(pivaloyloxy)ethyl penicillanate l-oxide,
l-(ethoxycarbonyloxy)ethyl penicillanate lB-oxide,
methoxycarbonyloxymethyl penicillanate lB-oxide,
¦ ethoxycarbonyloxymethyl penlcillanate lB-oxide,
25 I i~obutoxycarbonyloxymethyl penicillanate lB-oxide, ,
l-(methoxycarbonyloxy~ethyl penicillanate lB-oxide,
l-(butoxycarbonyloxy)ethyl penicillanate lB-oxide,
¦ I-(acetoxy)ethyl penicillanate lB-oxide, _.
-41 -
: . i
;l
l-(butyryloxy)ethyl penicillanate lB-oxide and .
l-(pivaloyloxy)ethyl penicillanate 13-oxide, .
respectively.` This affords:
. ' ,' , .. ,
penicillanic acid l,l-dioxide,
¦ acetoxymetnyl penicillanate l,l-dioxide,
ropionyloxymethyl penicillanate l,l-dioxlde,
pivaloyoxyme~hyl penicillanate l,l-dioxide,
acetoxymethyl penicillanate l,l-dioxide7
l propionyloxymethyl penicillanate l,l-tioxide,
10 ¦ pivaloyloxymethyl penicillanate l,l-dioxide,
3-phtha1idyl penicillanate l,l-dioxide,
I, 3-phthalidyl penicillanate l,l-dioxide,
(ethoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
~ methoxycarbonyloxymethyl penicillanate l,l-dioxide, -
15 ¦1 ethoxycarbonyloxymethyl penicillanate l,l-dioxide,
¦ isobutoxycarbonyloxymethyl penicillanate l,l-dioxide,
l-(methoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
l-(butoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
~ l-(acetoxy)ethyl penicillanate l,l-dioxide,
20 ¦ l-(butyryloxy)éthyl penicillanate l,l-di,oxide,
¦ l-(pivaloyloxy)ethyl penicillanate l,l-dioxide,
¦ l-(ethoxycarbonyloxy)ethyl ?enicillanate l,l-dioxide, ¦ ;
¦ methoxycarbonyloxymethyl penicillanate l,l-dloxide, . ¦
. ~ ethoxycarbonyloxymethyl penicillanate l,l-dioxide,
isobutoxycsrbonyloxymethyl penicillanate l,l-dioxide,
l-(methoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
l-(butoxycarbonyloxy)ethyl penicillanate l,l-dioxide,
l-(acetoxy)ethyl penicillanate l.l-dioxide, .
I¦ l-(bu~yryloxy)ethyl penicillanate l,l-dioxide and
30 1¦ l-(pivaloyloxy)ethyl penicillanate l,l-dioxide,
respectively.
- 42 -
, !
,
}
i~
llg~ 1,
l .
EXA~PLE 19
Oxidacion of benzyl penicillanate l~-oxide and benzyl penicillanate
18-oxide with 3-chloroperbenzoic acid, according to the procedure of Example
¦ 17, produces, in each case, benzyl penicillanate l,l-dioxide.
¦In like manner, oxidation of 4-nitrobenzyl penicillanate l~-oxide t
and 4-nitrobenzyl penicillanate l~-oxide with 3-chloroperbenzoic acid, accordin t
to the procedure of ~xample 17, produces 4-nitrobenzyl penicillanate 1,1- ¦ r
dioxide. '
. ' ' . .
EXAMPLE 20
- Penicillanic Acid l,l-Dioxide
i aydrogenolysis of 4-nitrobenzyl penicillanate l,l-dioxide, according
to the procedure of Example 3, affords penicillanic acid l,l-dioxide.
EXAMPLE 21
Sodium Penicillanate l,l-Dioxide
I .
.
15 ¦ To a stlrred solution of 32.75 g. (0.14 mole) of penicillanic acid
¦ l,l-dioxide in 450 ml. of ethyl acetate was added a solution of 25.7 g. of
sodium 2-ethylhexanoate (0.155 mole) in 200 ml. of ethyl acetace. The resultin -j
solution was stirred for 1 hour and then an addi'tional 10% excess of sodium
2-ethylhexanoate in a small volume of'ethyl acetate was added. Product im-
', 20 mediately began to precipitate. Stirring was continued for 30 minutes and
then the precipitate was removed by filtration. It was washed'sequentially wit t
ethyl acetate, with 1:1 ethyl acetate-ether and with ether. The solid was then
drled over phospnorus pentoxide, at ca. 0.1 r~m of Hg'for 16 hours at 25C., 1
giving 36.8 g. of the title sodium salt, contaminated with a small amount of
25 ¦ ethyl acetate. The ethyl acetate content was reduced by heating to 100C.
. I ..
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. ' :. '~' .'': . .' , ' ' , '
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,
. ' ' , ~ ' ' . ''` .
. ~119~6~
for 3 hours under vacuum. The IR spectrum of this final product (KBr disc)
. ~showed absorptions at 1786 and 1608 cm 1. The N~R spectrum lD20) showet ab-
. s orptions at 1.48 (s, 3H), 1.62 ~s, 3H), 3.35 (d of d's, lH, J1~16Hz, J2=2Hz),
; 3.70 (d of t's, lH, J1~16Hz, J2~4Hz), 4.25 (s, lH) and 5.03 (t of d's, lH,
S Jl-4Hz, J2~2Hz)ppm. .
The title sodium salt can also be prepared using acetone ln place
of ethyl acetate.
!
~ . ., .
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' ' '
', ` . 1119
lll ~
l ` ~ l
EXA~L~ 2Z
Penicillanic Acld l,l-Dioxide
To a mixture of 7,600 ml. of water ant 289 ml. of glacial acetic ! -
acid was added, portionwise, 379.5 g. of potassium permanganate. This mixture
was stirred for 15 minutes, and then it was cooled to 0 C. To it was then
added, with stirring, a mixture which hat been prepared from 270 g. of penicil-
lanic acid, 260 ml. of 4~ sodium hydroxide and 2,400 ml. of water tPH 7.2),
and which had then been cooled to 8q C. The temperature rose to 15 C. during
¦ thi6 latter addition. Tl~e temperature of the resulting mixture was reduced
10 ¦ to 5 C. and the stirrin~ was continued for 30 minutes. To the reaction l ¦
mixture was then added 142.1 g. of sodium bisulfite, in portions, during 10
j minutes. The mixture was stirred for 10 minutes at 10 C., and then 100 g;
of supercel (a diatomaceous earth) was addèd. After a further 5 minuces of
Il stirring, the mixture was filtered. To the filtrate was added 4.0 liters of
15 ll ethyl acetate, and then the pH of the aqueous phase was lowered to 1.55 using
¦¦ 6N hydrochloric acid. Tbe ethyl acetate layer was removet and combined with
¦¦ several further ethyl acetate extracts. The combined organic layer was
¦ washed with water, dried t~gS04) and evaporated almost to dryness in vacuo
The slurry thus obtained was stirred with 700 ml. of ether at 10 C., for 20
20 ¦ minutes, and then the solid was collected by filtration. This a'forded
¦ 82.6 g. (26% yield) of the title compound having a melting point of 154-155.5
,1 C. ~-c.).
~! ~
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- 45 ~
.
'~ 6~ ~
t
EXAMPLE 23
l Pivaloyloxymethyl Penicillanate l,l-Dioxide_ _ _ _
¦ To a solution of 1.25 g. pivaloyoxymethyl penicillanate in 40 ml.
¦ of chloroform, cooled to ca. -15 C., was added 0.8 g. of 3-chloroperbenzoic
¦ acid. The mixture was stirred at ca. -15 C. for 20 minutes and tnen it was
allowed to warm to room temperature. Analysis of the resulting solution by
NMR indicated that it contained both the 1~- and lB-oxide.
The chloroform solution was concentrated to about 20 ml. and a
further 0.8 g. of 3-chloroperbenzoic acid was added. This mixture was
stirred overnight at room temperature, and then all the solvent was removed
by evaporation in vacuo. The residue was redissolved in ca 4 ml. of dichloro-
methane and 0.4 g. of 3-chloroperbenzoic acid was added. The mixture was
stirred for 3 hours and then the solvent was removed by evaporation in vacuo.
The residue was partitioned between ethyl acetate and water at pH 6.0, and
sodium bisulfite was added until a test for the presence of peroxides was
negative. The pH of the aqueous phase was raised to 8.0 and the layers
¦ were separated. The organic layer was washed with brine, dried using anhydroussodium sulfate and evaporated ln vacuo. The residue was dissolved in ether an~
~ reprecipitated by the addition of hexane. The resulting solid was recrystal-
lized from ether to give 0.357 g. of the title compound.
The NMR spectrum of the product (CDC13) showed absorptions at t
1.23 (s,9H), 1.50(s,3H), 1.67 (s,3H), 3.28 (m,2H), 4.45 (s,lH), 5.25 (m,lH)
and 5.78 (m,2H)ppm.
~ gl~4
EX~MPL~ 24
3-PhthalidYl Penicillanate l,l-Dioxide
To a solution of 713 mg. of 3-phthalidyl penicillanate in 3 ml.
of chloroform was added 0.430 g. of 3-chloroperbenzoic acid at ca. 10 C.
The mixture was stirred for 30 minutes and then a further 0.513 g. of 3-
chloroperbenzoic acid was added. The mixture was stirred for 4 hours at
room temperature, and then the solvent was removed by evaporation In vacuo.
The residue was partitioned between ethyl acetate and water at pH 6.0, and
sodium bisulfite was added to decompose any remQining peracid. The pH
of the aqueous phase was raised to 8.8. The layers were separated and the
organic phase was evaporated in vacuo. This afforded the title compound as a
foam. The NMR spectrum (CDC13) showed absorptions at 1.62 (m,6H), 3.3(m,2H),
4.52 (p,lH), 5.23(m,lH) and 7.63 (m,5~1)ppm.
. . .
. .
, .
. . '
":
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.: ' ' ~ ' '~
,
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11191 64
EXAMPLE 25
2,2,2-Trichloroethyl Penicillanate l,l~Dioxide
.,
To 100 mg. of 2,2,2-trichloroethyl penicillanate in a s~all volume
of chloroform was added 50 mg. of 3-chloroperbenzoic acid and the mixture was
stirred for 30 minutes. Examination of the reaction plOdlCt aL ti~is point
revealed that it was mostly sulfoxide (The NMR spectrum (CDCl3) showed
absorptions at 1.6 (s,3H), 1.77 (s,3H), 3.38(m,2H), 4.65 (s,lil), 4.85 ~m,2H)
and 5.37 ~m,lH)ppm.) A further 100 mg. of 3-chloroperbenzoic acid was added
and the mixture was stirred overnight. The solvent was then removed by
evaporation in vacuo, and the residue was partitioned between ethyl acetate
and water at pH 6Ø Sufficient sodium bisulfite was added to decompose the
excess peracid and then the pH was raised to 8.5. The organic phase was
6eparated, washed with brine and dried. Evaporation in vacuo afforded 65 mg.
of the title product. The NMR spectrum (CDC13) showed absorptions at 1.53
(8 , 3H), 1.72 (8 ? 3H), 3.47(m,2H), 4.5(s,lH), 4.6 (m,lH) and 4.8 (m,2H)ppm.
., .
- 48 -
. .
. , , I
: - .
~ ~ 11191~;~
¦ EXAMPLE 26
¦ 4-Nitrobenzyl Penicillanate l,l-Dioxide r
A solution of 4-nitrobenzyl penicillanate in chloroform was cooled
to about 15 C. and l eguivalent of 3-chloroperbenzoic acid was added. The
reaction mixture was stirred for 20 minutes. Examination of the reaction
mixture at this point by nuclear magnetic resonance spectroscopy-revealed
that it contained 4-nitrobenzyl penicillanate l-oxide. A further l equivalent ¦of 3-chloroperbenzoic acid was added and the reaction mixture was stirred
for 4 hours. At this point a further 1 equivalent of 3-chloropèrbenzoic
acid was added and the reaction mixture was stirred overnight. The solvent
was re ved by evaporation, and the residue was partitioned between ethyl
acetate and water at pH 8.5. The ethyl acetate layer was separated, washed
with water, dried and evaporated to give the crude product. The crude product
was purified by chromatography on silica ,~el, eluting with at 1:4 mixture
lS of ethyl acetate/chloroform.
The NMR spectrum of the product (CDCl3) showed absorptions at
1.35 (s, 3H), 1.58 (6, 3H), 3.45 (m, 2H), 4.42 (s, lH), 4.58 (m, lH),
5.30 (s, 2H) and 7.83 (q, 4H)ppm
, ,
. .
....,. .._ . .___
-,
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:. .
1119164
EXAMPLE 27
Penicillanic Acid l,l-Dioxide
To 0.54 g. of 4-nitrobenzyl penicillanate l,l-dioxide in 30 ml.
of methanol and 10 ml. of ethyl acetate was added 0.54 g. of 10% palladium-on-
carbon. The mixture was then shaken under an atmosphere of hydrogen at a
pressure of about 50 psig. until hydrogen uptake ceased. The reaction mixtur~
was filtered, and the solvent removed by evaporation. The residue was
partitioned between ethyl acetate and water at pH 8.5, and the water layer
was re ved. Fresh ethyl aceta~e was added and the pH was adjusted to 1.5.
The ethyl;acetate layer was removed, washed with water and dried, and then it
was evaporated ln vacuo. This afforded 0.168 g. of the title compound as a
crystalline solid.
EXAMPLE 28
Penicillanic Acid l,l-Dioxide '-
A stirred solution of 512 mg. of 4-nitrobenzyl penicillanate 1,1- t
dioxide in a mixture-of 5 ml. of acetonitrile and 5 ml. of water was cooled
to 0 C. and then a solution of 484 ~g. of sodium dithionite in 1.4 ml. of
l.ON sodium hydroxide was added portionwise over several minutes. The reaction
mixture was stirred for an additional 5 minutes and then it was diluted with
ethyl acetate and water at pH 8.5. The ethyl acetate layer was removed and
evaporated in ~acuo giving 300 mg. of starting material. ~resh ethyl acetate
was added to the aqueous phase and the pH was adjusted to 1.5. The ethyl
acetate was removed, drled and evaporated in vacuo giving 50 mg. of the title
compound. ~
. . . , , .
- 50 - ;
..~ ' ' ' . 'l
~ ~1191~4 '
EXAM~LE 29
l-Methyl-l-(acetoxy)ethyl'Penicillanate l,l-Dioxide
To 2.33 g. of penicillanic acid l,l-dioxide in 5 ml. of ~N-dimethyl-
formamide was added 1.9 ml. of ethyldiisopropylamine, followed by the dropwise
addition of 1.37 g. of l-methyl-l-(acetoxy)ethyl chloride, at ca 20 C. The
~ixture was stirred at ambient temperature overnight and then-the mixture was ' ;
diluted with ethyl acetate and with water. The layers were separated and ~;
- the ethyl acetate layer was washed with water~at pH 9. The ethyl acRta~
solution was then dried (Na2S04) and e~aporated in vacuo leaving 1.65 g. of
crude product as an oil. The oil solidified on standing in the refrigerator,
and it was then recrystallized from a mixture of chloroform and ether giving
material having a melting point of 90-92 C.
The NMR spectrum of the crude product (CDC13) showed absorpt~ons at
1.5 (6, 3H), 1.62 (s, 3H), 1.85 (s, 3H), 1.93 (s, 3H), 2.07 (s, 3H), 3.43
(m, 2H), 4.3 (s, lH) and 4.57 (m, lH)PPm-
. i
EXA~LE 30
The procedure of Example 29 is repeated, except that the l-methyl-
l-(acetoxy)ethyl chloride is replaced by the appropriate l-methyl-l-(alkanoylox ')~
ethyl chloride, to produce the following compounds:
l-methyl-l-(propionyloxy)ethyl penicillanate l,l-dioxide,
l-methyl-l-(pivaloyloxy)ethyl penicillanate l,l-dioxide and
l-methyl-l-(hexanoyloxy)ethyl penicillanic acid l,l-dioxide,
respectively.
~ ;4
.~
EXAMPLE 31 2
Penicillanic Acid l,l-Dioxide
To a stirred solution of 1.78 g. of penicillanic acid in water, at
pH 7.5, was added 1.46 ml. of 40% peracetic acid, followed by an additional
2.94 ml. of 40% peracetic acid 30 minutes later. The reaction mixture was
stirred for 3 days at room temperature and then it was diluted with ethyl
acetate and water. Solid sodium bisulfite was added to decompose excess
peracidS and then the pH was adjusted to 1.5. The ethyl acetate layer was
re ved, dried ~Na2S04) and evaporated in vacuo. The residue was a 3:2 mixture
of penicillanic acid l,l-dioxide and penicil}anic acid l-oxide.
!
. . .~. - . . - ~.................. `
111916~ ~
EXAMPLE 32
Pivaloyloxymethyl Penicillanate l,l-Dioxide
A stirred solution of 595 mg. of pivaloyloxymethyl penicillanate
l-oxide in 5 ml. of ethyl acetate was cooled to ca -15 C., and 5 mg. of
5 ¦ manganic acetylacetonate was added. To the dark brown mixture thus obtained
was added, during several minutes, 0.89 ml. of 40~ peracetic acid in small
amounts over several minutes. After 40 minutes the cooling bath was removed, t
and the mixture was stirred at ambient temperature for 3 days. The mixture
l was diluted with ethyl acetate and water at pH 8.5, and the ethyl acetate
10 ¦ layer was removed, dried and evsporated in vacuo. This afforded 178 mg.
i of material which was shown by NMR spectroscopy to be a mixture of pivaloyoxy-methyl penicillanate l,l-dioxide and pivaloyloxymethyl penicillanate l-oxide.
The above material was redissolved in ethyl acetate and reoxidized
l using 0.9 ml. of peracetic acid and 5 mg. of manganic acetylacetonate, as
15 1 described above, using a reaction time of 16 hours. The reaction mixture was
worked up as described above. This afforded 186 mg. of pivaloyloxymethyl
penicillanate l,l-dioxide.
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¦ PREPARATION A
¦ 6,6-Dibromopenicillanic Acid ln-Oxide
. ' .
¦ The title compound is prepared by oxidation of 6,6-dibromopenicillanic
¦acid with 1 equivalent of 3-chloroperbenzoic acid in tetrahydrofuran at 0-25C. '
5 ¦ for ca. 1 hour, according to the procedure of Harrison et al., Journal of the
Chemical Society (London) Perkin I, 1772 tl976).
¦ PREPARATION B
Benzyl 6.6-Dibromopenicillanate
To a solution of 54 g. (0.165 mole) of 6,6-dibromopenicillanic acid
in 350 ml. of N,N-dimethylacetamide was added 22.9 ml. (0.165 mole) of triethyl;
amine and the solution was stirred for 40 minutes. Ben~yl bromide (19.6 ml.,
0.165 mole) was added and the sesulting mixture was stirred at room temperature
for 48 hourfi. .The precipitated triethylamine hydrobromide was fil~ered off,
l and the filtrate was added to 1,500 ml. of ice-water, adjusted to pH 2. The
15 1 mLxture was extracted with ether, and the extracts were washed successively with
saturated sodium bicarbonate, water and brine. The dried (MgS04) ether solu-
. tion was evaporated in vacuo to give an off-white solid, which was recrys~al-
I lized from isopropanol. This afforded 70.0 g. (957. yield) of the title compoundl m.p. 75-76C. The IR spectrum (KBr disc) showed absorptions at 1795 and
20 1 1740 cm 1. The N~ spectrum (CDC13) showsd absorptions at 1.53 (s, 3H), l.S8
~ (o, 3H), 4. (s, lH~, 5.13 ~s, ZU), 5.72 (G, 13) aDd 7.37 (s, 53~pp~.
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¦ PREPAtATIOW C
Benzyl 6.6-Dibromopenicillanate l~-Oxide
¦¦ To a stirred solution of 13.4 g. (0.03 mole) of benzyl 6,~-dibromo-
I penicillanate in 200 ml. of dichloromethane was added a solution of 6.12 g.
(0.03 mole) of 3-chloroperbenzoic acid in 100 ml. of dichloromethane, at ca.
¦I 0C. Stirring was continued for 1.5 hours at ca. 0C. and then the reaction
i mixture was filtered. The filtrate was washed successively with SZ sodium
bicarbonate and water, and then it w~s dried (~a2SO4). Removal of the solvent
by evaporation in vacuo gave 12.5 g. of the title product as an oil. The oil
was induced to solidi~y by trituration under ether. Filtration then afforded
10.5 g. of benzyl 6,6-dibromopenicillanate l~-oxide as a solid. Ihe IR spec-
¦ trum (CHC13) showed absorptions at lôO0 and 1750 cm . The N~IR spectrum of
the product (CDC13) showed absorptions at 1~3 (s, 3H), l.S (s, 3H), 4.5 (s, lH)
5.18 (s, 2H), 5.2 (s, lH) and 7.3 (s, 5H)ppm.
PREPARATION D
l4-Nitrobenzyl Penicillanate
¦Reaction of the triethylamine salt of penicillanic acid with 4-nitro-
¦ benzyl bromide according to the procedure of Preparation B, affords 4-nitro-
benzyl ptnl lllanate.
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- PREPARAl'ION E
222,2-Trichloroeth,yl Penicillanate
To ~03 mg. of penicillanic acid in 10 ml. of dichloromethane was
added 25 mg. of diisopropylcarbodiimide followed by O.l9 ml. of 2,2,2-trichloro~ethanol. The mixture was stirred overnight and then the solvent was removed
by evaporation in vacuo. The crude product was purified by column chroma- :~
tography using eilica gel as the adsorbent and chloroform as the eluant.
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PREPARATION F
3-Phthalidyl Penicillanate ,
To a solution of 506 mg. of penicillanic acid in 2 ml. of N,N-
dimethylormamide was added 0.476 ml. of diisopropyietbylamine followed by
5 536 mg. of 3-phthalidyl bromide. The mixture was stirred overnight and then
it was diluted with ethyl acetate and water. The pH was adjusted to 3.0 and
the layers were separated. The organic layer was wasbed with water, and
then with water at pH 8.0, and then it was dried using anhydrous sodium sulfate
I The dried ethyl acetate solution was evaporated in vacuo giving 713 ~g. of the10 ¦title ester as an oil. The N~ spectrum (CDC13) showed absorptions at L
¦1.62 (m,6H), 3.3 (m,2H), 4.52 (s,lH), 5.23 (m,lH) and 7.63 (m,5H).
19~4
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PREPA~ATION G
PivaloyloxYmethyl Penicillanate
To 3.588 g. of 6,6~dibromopenicillanic acid in 10 ml. of N,N-
dimethylformamide was added 1.8 ml. of diisopropylethylamine, followed by 1.40
ml. of chloromethyl pivalate. The mixture was stirred overnight and then it
was diluted with ethyl acetate and water. The organic layer was removed and
¦washed successively with water at pH 3.0 and water at pH 8Ø The ethyl acetat
solution was dried (Na2SO4) and then evaporated in vacuo to give pivaloyloxy-
methyl 6,6-dibromopenicillanate as an amber oil (3.1 g.) which slowly
crystallized.
The above ester was dissolved in lO0 ml. of methanol, and then
3.1 g. of 10% palladium-on-carbon and 1.31 g. of potassium bicarbonate in
20 ml. of water were added. The mixture was shaken under hydrogen at atmospher: c
pressure until hydrogen uptake ceased. The reaction mixture was filtered and
the methanol was removed by evaporation in vacuo. The residue was partitioned
between water and ethyl acetate at pH 8, and then the organic layer was removed.
The latter was dried (Na2SO4) and evaporated in vacuo to give 1.25 g. of the
title compound. The NMR spectrum (CDC13) showed absorptions at 1.23 (s,gH),
1.5 (s,3H), 1.67 (s,3H), 3.28 (m,2H), 4.45 (s,lH), 5.25 (m,lH) and 5.78 (m,2H)
20 ppm. .
111~164
` PREPARATION H
4-Nitrobenzyl Penicillanate
To a stirred solution of 2.14 g. of penicillanic acid and 2.01 ml.
of ethyldiisopropylamine in 10 ml. of N,N-dimethylformamide was added dropwise
2.36 g. of 4-nitrobenzyl bromide, at ca. 20C. The mixture was stirred at
ambient temperature overnight, and then it was diluted with ethyl acetate
and water. The layers were separated and the ethyl acetate layer was washed
with water at pH 2.5, followed by water at pH 8.5. The ethyl acetate solution
was then dried (Na2S04) and evaporated in vacuo leaving 3.36 g. of the title
compound. -
The NMR spectrum of the product (in CDC13) showed absorptions at
1.45 (s, 3H), 1.68 (s, 3H), 3.32 (m, 2H), 4.50 (s, lH), 5.23 (m, lH),
5.25 (s, 2H) and 7.85 (q, 4H) ppm.
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